1. Field of the Invention
The present invention relates generally to fluid pumps and more particularly to multiple port, dual diameter fluid pumps.
2. Description of the Prior Art
Multiple port linear pumps have been used in the biosciences as a means to dispense different fluids from the same pump. Multiple ports also provide the capability to rinse the pump between dispensing strokes. For example, U.S. Pat. No. 6,666,666 shows such a pump. Prior art pumps however have single pistons of fixed diameter. To dispense micro-liter quantities of fluid, they require extremely tiny strokes. This leads to inaccuracy.
What is badly needed is a multiple port, dual or multiple diameter pump for the dispensing of fluids where micro-liters can be dispensed with a reasonably controllable length stroke.